This invention relates to the production of radiopharmaceuticals and more particularly to production of potassium-38.
The invention described herein was made or conceived in the course of, or under a contract with, the United States Department of Energy.
Potassium-38 has ideal physiological and physical characteristics for use as a radiopharmaceutical. Physiologically potassium-38 is preferentially extracted into the heart, while its decay characteristics, 200% abundance of positron annihilation photons (E.sub..beta. +.sup.= 2.7 MeV) and approximately 100% abundance of 2.17 MeV photons make it highly suitable for positron emission tomography. Further, its halflife of approximately 7.62 minutes allows its use with a relatively low radiation dosage to the patient. This combination of characteristics makes potassium-38 an ideal agent for the quantitative measurement of myocardial perfusion.
While the use of potassium-38 in nuclear medicine has been suggested, and potassium-38 has been produced for nuclear physics experiments, prior to the subject invention there was no known method for its routine production in quantities and form suitable for use as a radiopharmaceutical. Further, methods previously known in nuclear physics did not contemplate the rapid preparation of the product potassium-38 for use as a radiopharmaceutical.
By "suitable for use as a radiopharmaceutical" herein is meant an essentially pure and sterile solution of potassium-38, and its decay products, in water having a total activity, at the time of injection, of from 1 to 10 mCi, in a volume of from 1-5 milliliters.